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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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#ifndef SHARE_VM_INTERPRETER_LINKRESOLVER_HPP

#define SHARE_VM_INTERPRETER_LINKRESOLVER_HPP

#include "oops/method.hpp"

// All the necessary definitions for run-time link resolution.

// CallInfo provides all the information gathered for a particular

// linked call site after resolving it. A link is any reference

// made from within the bytecodes of a method to an object outside of

// that method. If the info is invalid, the link has not been resolved

// successfully.

class CallInfo : public StackObj {

 public:

  // Ways that a method call might be selected (or not) based on receiver type.

  // Note that an invokevirtual instruction might be linked with no_dispatch,

  // and an invokeinterface instruction might be linked with any of the three options

  enum CallKind {

    direct_call,                        // jump into resolved_method (must be concrete)

    vtable_call,                        // select recv.klass.method_at_vtable(index)

    itable_call,                        // select recv.klass.method_at_itable(resolved_method.holder, index)

    unknown_kind = -1

  };

 private:

  Klass*       _resolved_klass;         // static receiver klass, resolved from a symbolic reference

  Klass*       _selected_klass;         // dynamic receiver class (same as static, or subklass)

  methodHandle _resolved_method;        // static target method

  methodHandle _selected_method;        // dynamic (actual) target method

  CallKind     _call_kind;              // kind of call (static(=bytecode static/special +

                                        //               others inferred), vtable, itable)

  int          _call_index;             // vtable or itable index of selected class method (if any)

  Handle       _resolved_appendix;      // extra argument in constant pool (if CPCE::has_appendix)

  Handle       _resolved_method_type;   // MethodType (for invokedynamic and invokehandle call sites)

  void set_static(Klass* resolved_klass, const methodHandle& resolved_method, TRAPS);

  void set_interface(Klass* resolved_klass, Klass* selected_klass,

                     const methodHandle& resolved_method,

                     const methodHandle& selected_method,

                     int itable_index, TRAPS);

  void set_virtual(Klass* resolved_klass, Klass* selected_klass,

                   const methodHandle& resolved_method,

                   const methodHandle& selected_method,

                   int vtable_index, TRAPS);

  void set_handle(const methodHandle& resolved_method,

                  Handle resolved_appendix, Handle resolved_method_type, TRAPS);

  void set_handle(Klass* resolved_klass,

                  const methodHandle& resolved_method,

                  Handle resolved_appendix, Handle resolved_method_type, TRAPS);

  void set_common(Klass* resolved_klass, Klass* selected_klass,

                  const methodHandle& resolved_method,

                  const methodHandle& selected_method,

                  CallKind kind,

                  int index, TRAPS);

  friend class LinkResolver;

 public:

  CallInfo() {

#ifndef PRODUCT

    _call_kind  = CallInfo::unknown_kind;

    _call_index = Method::garbage_vtable_index;

#endif //PRODUCT

  }

  // utility to extract an effective CallInfo from a method and an optional receiver limit

  Klass*  resolved_klass() const                 { return _resolved_klass; }

  Klass*  selected_klass() const                 { return _selected_klass; }

  methodHandle resolved_method() const           { return _resolved_method; }

  methodHandle selected_method() const           { return _selected_method; }

  Handle       resolved_appendix() const         { return _resolved_appendix; }

  Handle       resolved_method_type() const      { return _resolved_method_type; }

  BasicType    result_type() const               { return selected_method()->result_type(); }

  CallKind     call_kind() const                 { return _call_kind; }

  int          call_index() const                { return _call_index; }

  int          vtable_index() const {

    // Even for interface calls the vtable index could be non-negative.

    // See CallInfo::set_interface.

    assert(has_vtable_index() || is_statically_bound(), "");

    assert(call_kind() == vtable_call || call_kind() == direct_call, "");

    // The returned value is < 0 if the call is statically bound.

    // But, the returned value may be >= 0 even if the kind is direct_call.

    // It is up to the caller to decide which way to go.

    return _call_index;

  }

  int          itable_index() const {

    assert(call_kind() == itable_call, "");

    // The returned value is always >= 0, a valid itable index.

    return _call_index;

  }

  // debugging

#ifdef ASSERT

  bool         has_vtable_index() const          { return _call_index >= 0 && _call_kind != CallInfo::itable_call; }

  bool         is_statically_bound() const       { return _call_index == Method::nonvirtual_vtable_index; }

#endif //ASSERT

  void         verify() PRODUCT_RETURN;

  void         print()  PRODUCT_RETURN;

};

// Condensed information from constant pool to use to resolve the method or field.

//   resolved_klass = specified class (i.e., static receiver class)

//   current_klass  = sending method holder (i.e., class containing the method

//                    containing the call being resolved)

//   current_method = sending method (relevant for field resolution)

class LinkInfo : public StackObj {

  Symbol*     _name;            // extracted from JVM_CONSTANT_NameAndType

  Symbol*     _signature;

  Klass*      _resolved_klass;  // class that the constant pool entry points to

  Klass*      _current_klass;   // class that owns the constant pool

  methodHandle _current_method;  // sending method

  bool        _check_access;

  constantTag _tag;

 public:

  enum AccessCheck {

    needs_access_check,

    skip_access_check

  };

  LinkInfo(const constantPoolHandle& pool, int index, methodHandle current_method, TRAPS);

  LinkInfo(const constantPoolHandle& pool, int index, TRAPS);

  // Condensed information from other call sites within the vm.

  LinkInfo(Klass* resolved_klass, Symbol* name, Symbol* signature, Klass* current_klass,

           AccessCheck check_access = needs_access_check,

           constantTag tag = JVM_CONSTANT_Invalid) :

    _resolved_klass(resolved_klass),

    _name(name), _signature(signature), _current_klass(current_klass), _current_method(methodHandle()),

    _check_access(check_access == needs_access_check), _tag(tag) {}

  LinkInfo(Klass* resolved_klass, Symbol* name, Symbol* signature, methodHandle current_method,

           AccessCheck check_access = needs_access_check,

           constantTag tag = JVM_CONSTANT_Invalid) :

    _resolved_klass(resolved_klass),

    _name(name), _signature(signature), _current_klass(current_method->method_holder()), _current_method(current_method),

    _check_access(check_access == needs_access_check), _tag(tag) {}

  // Case where we just find the method and don't check access against the current class

  LinkInfo(Klass* resolved_klass, Symbol*name, Symbol* signature) :

    _resolved_klass(resolved_klass),

    _name(name), _signature(signature), _current_klass(NULL), _current_method(methodHandle()),

    _check_access(false), _tag(JVM_CONSTANT_Invalid) {}

  // accessors

  Symbol* name() const               { return _name; }

  Symbol* signature() const          { return _signature; }

  Klass* resolved_klass() const      { return _resolved_klass; }

  Klass* current_klass() const       { return _current_klass; }

  methodHandle current_method() const { return _current_method; }

  constantTag tag() const            { return _tag; }

  bool check_access() const          { return _check_access; }

  char* method_string() const;

  void         print()  PRODUCT_RETURN;

};

// Link information for getfield/putfield & getstatic/putstatic bytecodes

// is represented using a fieldDescriptor.

// The LinkResolver is used to resolve constant-pool references at run-time.

// It does all necessary link-time checks & throws exceptions if necessary.

class LinkResolver: AllStatic {

  friend class klassVtable;

  friend class klassItable;

 private:

  static methodHandle lookup_method_in_klasses(const LinkInfo& link_info,

                                               bool checkpolymorphism,

                                               bool in_imethod_resolve, TRAPS);

  static methodHandle lookup_method_in_interfaces(const LinkInfo& link_info, TRAPS);

  static methodHandle lookup_polymorphic_method(const LinkInfo& link_info,

                                                Handle *appendix_result_or_null,

                                                Handle *method_type_result, TRAPS);

 JVMCI_ONLY(public:) // Needed for CompilerToVM.resolveMethod()

  // Not Linktime so doesn't take LinkInfo

  static methodHandle lookup_instance_method_in_klasses (

                                       Klass* klass, Symbol* name, Symbol* signature, TRAPS);

 JVMCI_ONLY(private:)

  // Similar loader constraint checking functions that throw

  // LinkageError with descriptive message.

  static void check_method_loader_constraints(const LinkInfo& link_info,

                                              const methodHandle& resolved_method,

                                              const char* method_type, TRAPS);

  static void check_field_loader_constraints(Symbol* field, Symbol* sig,

                                             Klass* current_klass,

                                             Klass* sel_klass, TRAPS);

  static methodHandle resolve_interface_method(const LinkInfo& link_info, Bytecodes::Code code, TRAPS);

  static methodHandle resolve_method          (const LinkInfo& link_info, Bytecodes::Code code, TRAPS);

  static methodHandle linktime_resolve_static_method    (const LinkInfo& link_info, TRAPS);

  static methodHandle linktime_resolve_special_method   (const LinkInfo& link_info, TRAPS);

  static methodHandle linktime_resolve_virtual_method   (const LinkInfo& link_info, TRAPS);

  static methodHandle linktime_resolve_interface_method (const LinkInfo& link_info, TRAPS);

  static void runtime_resolve_special_method    (CallInfo& result,

                                                 const methodHandle& resolved_method,

                                                 Klass* resolved_klass,

                                                 Klass* current_klass,

                                                 Handle recv,

                                                 bool check_access, TRAPS);

  static void runtime_resolve_virtual_method    (CallInfo& result,

                                                 const methodHandle& resolved_method,

                                                 Klass* resolved_klass,

                                                 Handle recv,

                                                 Klass* recv_klass,

                                                 bool check_null_and_abstract, TRAPS);

  static void runtime_resolve_interface_method  (CallInfo& result,

                                                 const methodHandle& resolved_method,

                                                 Klass* resolved_klass,

                                                 Handle recv,

                                                 Klass* recv_klass,

                                                 bool check_null_and_abstract, TRAPS);

  static void check_field_accessability(Klass* ref_klass,

                                        Klass* resolved_klass,

                                        Klass* sel_klass,

                                        const fieldDescriptor& fd, TRAPS);

  static void check_method_accessability(Klass* ref_klass,

                                         Klass* resolved_klass,

                                         Klass* sel_klass,

                                         const methodHandle& sel_method, TRAPS);

  // runtime resolving from constant pool

  static void resolve_invokestatic   (CallInfo& result,

                                      const constantPoolHandle& pool, int index, TRAPS);

  static void resolve_invokespecial  (CallInfo& result, Handle recv,

                                      const constantPoolHandle& pool, int index, TRAPS);

  static void resolve_invokevirtual  (CallInfo& result, Handle recv,

                                      const constantPoolHandle& pool, int index, TRAPS);

  static void resolve_invokeinterface(CallInfo& result, Handle recv,

                                      const constantPoolHandle& pool, int index, TRAPS);

  static void resolve_invokedynamic  (CallInfo& result,

                                      const constantPoolHandle& pool, int index, TRAPS);

  static void resolve_invokehandle   (CallInfo& result,

                                      const constantPoolHandle& pool, int index, TRAPS);

 public:

  // constant pool resolving

  static void check_klass_accessability(Klass* ref_klass, Klass* sel_klass, TRAPS);

  // static resolving calls (will not run any Java code);

  // used only from Bytecode_invoke::static_target

  static methodHandle resolve_method_statically(Bytecodes::Code code,

                                                const constantPoolHandle& pool,

                                                int index, TRAPS);

  static void resolve_field_access(fieldDescriptor& result,

                                   const constantPoolHandle& pool,

                                   int index,

                                   const methodHandle& method,

                                   Bytecodes::Code byte, TRAPS);

  static void resolve_field(fieldDescriptor& result, const LinkInfo& link_info,

                            Bytecodes::Code access_kind,

                            bool initialize_class, TRAPS);

  static void resolve_static_call   (CallInfo& result,

                                     const LinkInfo& link_info,

                                     bool initialize_klass, TRAPS);

  static void resolve_special_call  (CallInfo& result,

                                     Handle recv,

                                     const LinkInfo& link_info,

                                     TRAPS);

  static void resolve_virtual_call  (CallInfo& result, Handle recv, Klass* recv_klass,

                                     const LinkInfo& link_info,

                                     bool check_null_and_abstract, TRAPS);

  static void resolve_interface_call(CallInfo& result, Handle recv, Klass* recv_klass,

                                     const LinkInfo& link_info,

                                     bool check_null_and_abstract, TRAPS);

  static void resolve_handle_call   (CallInfo& result,

                                     const LinkInfo& link_info, TRAPS);

  static void resolve_dynamic_call  (CallInfo& result, Handle bootstrap_specifier,

                                     Symbol* method_name, Symbol* method_signature,

                                     Klass* current_klass, TRAPS);

  // same as above for compile-time resolution; but returns null handle instead of throwing

  // an exception on error also, does not initialize klass (i.e., no side effects)

  static methodHandle resolve_virtual_call_or_null  (Klass* receiver_klass,

                                                     const LinkInfo& link_info);

  static methodHandle resolve_interface_call_or_null(Klass* receiver_klass,

                                                     const LinkInfo& link_info);

  static methodHandle resolve_static_call_or_null   (const LinkInfo& link_info);

  static methodHandle resolve_special_call_or_null  (const LinkInfo& link_info);

  static int vtable_index_of_interface_method(Klass* klass, const methodHandle& resolved_method);

  // same as above for compile-time resolution; returns vtable_index if current_klass if linked

  static int resolve_virtual_vtable_index  (Klass* receiver_klass,

                                            const LinkInfo& link_info);

  // static resolving for compiler (does not throw exceptions, returns null handle if unsuccessful)

  static methodHandle linktime_resolve_virtual_method_or_null  (const LinkInfo& link_info);

  static methodHandle linktime_resolve_interface_method_or_null(const LinkInfo& link_info);

  // runtime resolving from constant pool

  static void resolve_invoke(CallInfo& result, Handle recv,

                             const constantPoolHandle& pool, int index,

                             Bytecodes::Code byte, TRAPS);

  // runtime resolving from attached method

  static void resolve_invoke(CallInfo& result, Handle& recv,

                             const methodHandle& attached_method,

                             Bytecodes::Code byte, TRAPS);

};

#endif // SHARE_VM_INTERPRETER_LINKRESOLVER_HPP